If your display doesn't respond to touch

On iPad Pro 11-inch and iPad Pro 12.9-inch (3rd generation): Press and immediately release the Volume Up button, then press and immediately release the Volume Down button. Press and hold the Power button until the device restarts.

On iPhone 8 and later: Press and quickly release the Volume Up button. Then press and quickly release the Volume Down button. Then press and hold the Side button until you see the Apple logo.

On an iPhone 7 or iPhone 7 Plus: Press and hold both the Side and Volume Down buttons for at least 10 seconds, until you see the Apple logo.

On an iPhone 6s and earlier, iPad, or iPod touch: Press and hold both the Home and the Top (or Side) buttons for at least 10 seconds, until you see the Apple logo.